The present invention is an improvement on that type of wood member cutting apparatus shown in prior U.S. Pat. Nos. 3,080,895; 3,229,732 and 3,380,494, issued to George L. Mayo.
In common with these prior art apparatuses, the present invention is used for cutting wood members used in the manufacturing of wooden roof and floor trusses and for many other purposes where precision repetitive cutting of members on a production basis is required. As in the prior patented apparatuses, the present invention includes a stationary base frame, a first gang of power saws and first conveyor means mounted near one end of the base frame, a carriage on the base frame movable toward and away from the first gang of saws and first conveyor means, and a second gang of saws and second coacting conveyor means mounted on the carriage. The present invention, like the prior patented apparatuses, includes a driving system for the conveyor means and the carriage and a means to gage the lengths of wood members being cut in the apparatus.
The prior patented apparatuses, while quite efficient in the overall, possess certain definite drawbacks which are fully eliminated in the present invention. The most serious of these drawbacks is the comparatively limited mobility of the cut-off saws in the two gangs and the complete lack of any independent vertical adjustment of the saws in the gangs. As a result, the saws of the prior patented apparatuses are limited to 90 degrees of rotation or pivoting to avoid interference with the workpieces being cut, and are also restricted to cutting with only one segment of the circular blade of each saw.
These restrictions are eliminated in the present invention by the provision of an independent vertical adjustment for each saw in the two gangs of saws within a vertical datum or reference plane common to each saw gang. This critical adjustment together with an expanded double pantograph precision support and guidance mechanism for each saw greatly increases the rotational mobility of each saw to such an extent that each saw independently can rotate a fully 180 degrees around the axis of a chord across the saw blade lying in the vertical datum plane for such blade.
This improved arrangement enables two segments on diametrically opposite parts of each saw blade to be utilized for cutting wood members, instead of one segment only, thus increasing the number of angle cuts which can be made during each pass of a wood member through the apparatus and also increasing the variety of types of cuts which can be made. The improved arrangement enables the addition of another saw in each of the two gangs, compared to the arrangements in the prior patented apparatuses, where individual saw rotation is limited to 90 degrees.
Another drawback of the prior art which this invention completely overcomes is the use of a very long torque shaft for driving the conveyor system. Such a long shaft is difficult to support and is likely to be damaged resulting in poor operation of the conveyor system and expensive repairs. To overcome this difficulty, an improved conveyor drive in this invention eliminates entirely the use of a long torque shaft in the conveyor system. Instead, the drive employs an arrangement of electromagnetic clutch devices associated with chain and sprocket gearing powered directly by a single drive unit to operate both the stationary and carriage mounted conveyor components in unison or independently as particular requirements dictate to greatly increase the precision and versatility of the conveyor system. The improved arrangement enables the use of separable auxiliary work conveyors directly driven by the drive means of the primary conveyors when long wood members are involved.
Another important improvement feature over the prior art is the provision in the present invention of a precision wood member measuring device on the front of the base frame of the apparatus which can automatically stop the carriage and thus position the two saw gangs for cutting wood members of any required length with high precision.
The improved more versatile conveyor system also enables certain compound angle cuts to be made on wooden members which are not possible in the prior art.
Other features and advantages of the present invention will be made apparent to those skilled in the art during the course of the following detailed description.